Method of hardening cast articles



April 10, 1934. F. E. MccLEARY Er AL r METHOD OF HARDENING CAST ARTICLES Original Filed April 26, `1930 WOM M TmN .im NLMY E c A m VcQR m NMMIV/ ./T. .RR

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Patented Apr. 10, 1934 METHOD oF HARDENING CAST ARTICLES Fred E. McCleary, Detroit, Kurt C. Babu, Clawson, and Harry Rayner, Detroit, Mich., assigncrs to Chrysler Corporation, Detroit, Mich., a corporation of Delaware Original application April 26, 1930, Serial No. 447,722. Divided and this application January 9, 1932, Serial No. 585,765

1 Claim.

This invention relates to an improved method for hardening selected portions of metal castings, particularly the portions of cylinder block castings in which valve seats are formed, and it is a v division of our copending application, Serial No.

447,722, iiled April 26th, 1930, which issued April 5th, 1932, as Patent No. 1,852,621.

The main objects of this invention are to provide tempering apparatus for hardening the top wall of a cylinder block casting so as to produce hardened valve seats which will withstand deformation by the pounding action of the valve heads to which the seats are normally subjected; to provide a method for treating cylinder blocks or other castings during the latter stages of progressive movement of the castings while they are in the process of formation and before the temperature has decreased after solidification; and to provide a method of this kind by which selected portions of castings are suddenly cooled immediately after the castings are removed from their moulds so as to utilize the heat remaining therein after the metal has solidified.

An illustrative embodiment of this invention is shown in the accompanying drawing in which: Fig. l is a diagrammatic side elevation, partly in section, of our improved apparatus for hardening selected portions of cast articles.

Fig. 2 is a transverse vertical section taken on line 2--2 of Fig. 1.

A' blower is a tapered conduit 19 which extendsv Fig. 3 is a transverse vertical section taken on line 3 3 of Fig. 1.

In the form shown, the apparatus comprises a floor or base part 1 on the respectively opposite sides of one end portion of which are mounted pairs of vertical supports, 2, 3, and 4. The upper ends of each pair of supports 2, 3, and 4, are joined together by transverse angle bars, 5, 6, and 7, respectively, on which are mounted spaced longitudinal angle bars 8 and 9. This construction forms a substantially rectangular frame for supporting at one end a motor 10 and at the other end a blower 11. The blower has a casing 12 which is riveted at 13 to the longitudinal bars 8 i and 9. A belt 14 is provided for driving the rotor 15 of the blower 11.

Mounted on the opposite end of the base 1 is a U-shaped support 16 to which one end of a central longitudinally extending beam 17 of T- shaped cross section is secured by brackets 18. The other end of the central beam 17 is secured by brackets 18 to the transverse angle har 5 of the rectangular frame structure.

Communicating with the casing 11 of the longitudinally of the above structure and is suspended by U-shaped straps 20 from the central beam 17. The conduit 19 has a plurality of spaced downwardly extending outlet pipes 21 in which valves 22 are mounted and the conduit 19 is provided with spaced valves 23 by which the discharge of the cooling medium from groups of the outlet pipes 21 may be regulated. The valves 22 in the outlet pipes permit independent regulation of the discharge of cooling medium from each outlet.

A conveyor having an endless belt 24 is mounted between the side supports 2, 3, and 4, and the legs of the U-shaped end support 16 directly below the outlets 21 of the conduit 19. The belt 24 is mounted on rollers 25 and 26 which are journaled on upright plates 27 and 28 rigidly mounted on the base 1. Driving mechanism, not shown, is provided for moving the top layer of the endless belt 24 in the direction indicated by the arrow 29. A similar conveyor having an endless belt 30 mounted at one end on a roller 31 which is located adjacent the roller 25 feeds castings, such as cylinder blocks, to the belt 24 by which they are conveyed past the successive outlets of the conduit 19.

In practice, the moulds in which the castings 32 are formed are placed on the belt 30 and the metal is poured thereinto during continuous operation of the conveyors. After the metal is solidified the rigid structure oi the moulds and the sand is removed by conventional means and the castings are moved along at a suitable rate of speed so as to pass them under the outlet pipes 21before their temperature has fallen below the critical temperature of the metal of which they are formed. The blasts of cooling medium to which the castings, or cylinder blocks shown in the illustration, are successively subjected, are directed upon the top Wall of the cylinder blocks so as to harden the material thereof in which the valve seats are subsequently formed. This chilling action hardens the portions of the block which are subjected to violent pounding during operation of an engine without making the body of the structure hard and brittle.

Air may be used as a cooling medium and if desired, atomized oil or water may be mixed with the air current and sprayed upon the castings, together with the air current. In some instances where a less rapid rate of cooling is desired, steam may be used as a cooling medium, either alone or in conjunction with air and atomized oil. The rate of discharge of the cooling medium may be proportioned in accordance with the size and quantity of metal in the castings either by individual control of the cooling medium outlets or by collective control of selective groups of such outlets.

Although but one specic embodiment of our invention is shown illustrating a hardening operation on cylinder blocks, it is understood that the method is adapted for the heat treatment of cast articles of various types and that various changes may be made without departing from the spirit of our invention, and it is not our intention to limit its scope other than by the terms of the appended claim.

We claim:

In manufacturing cast articles, the method of hardening selected surfaces thereof which consists in moving said heated articles in a predetermined course causing a confined air current to flov.T in the same direction as the movement of said articles in a course corresponding with and adjacent to the path of movement thereof, and subjecting said selected portions of each article to successive discharges of said air current at spaced intervals throughout the course of movement of said articles, the successive air discharges increasing in temperature as the temperature of said article is lowered during its movement.

FRED E. MCCLEARY.

KURT C. BABO.

HARRY RAYNER. 

